屬性級別注解
添加方式：
寫在屬性字段上面
寫在屬性的get訪問器的上面
@Id
必須，定義了映射到數(shù)據(jù)庫表的主鍵的屬性，一個實體類可以有一個或者多個屬性被映射為主鍵，可置于主鍵屬性或者getXxx()前，注意：如果有多個屬性定義為主鍵屬性，該實體類必須實現(xiàn)serializable接口
@SequenceGenerator
@GeneratedValue
@GeneratedValue(strategy=GenerationType,generator=""):可選，用于定義主鍵生成策略
strategy表示主鍵生成策略，取值有：
GenerationType.AUTO:根據(jù)底層數(shù)據(jù)庫自動選擇（默認(rèn)）
GenerationType.INDENTITY:根據(jù)數(shù)據(jù)庫的Identity字段生成
GenerationType.SEQUENCE:使用Sequence來決定主鍵的取值
GenerationType.TABLE:使用指定表來決定主鍵取值，結(jié)合@TableGenerator使用
@Column
@Column-可將屬性映射到列，使用該注解來覆蓋默認(rèn)值，@Column描述了數(shù)據(jù)庫表中該字段的詳細(xì)定義，這對于根據(jù)JPA
注解生成數(shù)據(jù)庫表結(jié)構(gòu)的工具非常有作用。
常用屬性：
name:可選，表示數(shù)據(jù)庫表中該字段的名稱，默認(rèn)情形屬性名稱一致
nullable:可選，表示該字段是否允許為null,默認(rèn)為true
unique:可選，表示該字段是否為唯一標(biāo)識，默認(rèn)為false
length:可選，表示該字段的大小，僅對String類型的字段有效，默認(rèn)值225，主鍵不能使用默認(rèn)值
insertable:可選，表示在ORM框架執(zhí)行插入操作時，該字段是否應(yīng)出現(xiàn)INSERTRT語句中，默認(rèn)為true
updateable:可選，表示在ORM框架執(zhí)行更新操作時，該字段是否應(yīng)該出現(xiàn)在UPDATE語句中，默認(rèn)為true。對于已經(jīng)創(chuàng)建
就不可以更改的字段，該屬性非常有用
@Embedded
@Embedded是注釋屬性的，表示該屬性的類是嵌入類。
注意：同時嵌入類也必須標(biāo)注@Embeddable注解
@EmbeddedId
@EmbeddedId使用嵌入式主鍵類實現(xiàn)復(fù)合主鍵
注意：嵌入式主鍵類必須實現(xiàn)Serializable接口、必須有默認(rèn)的public無參數(shù)的構(gòu)造方法、必須覆蓋equals和hashCode方法
@Lob
@Version
@Basic
@Transient
可選，表示該屬性并非一個到數(shù)據(jù)庫表的字段的映射，ORM框架將忽略該屬性，如果一個屬性并非數(shù)據(jù)庫表的字段映射，就
務(wù)必將其標(biāo)示為@Transient，否則ORM框架默認(rèn)其注解為@Basic
實例：
hibernate.properties配置：
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<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property> <!-- <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> <property name="hibernate.connection.url">jdbc:mysql:///hibernate_struts_stumanager</property> --> <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/mypage</property> <property name="hibernate.connection.username">root</property> <property name="hibernate.connection.password">root</property> <property name="hibernate.show_sql">false</property> <property name="hibernate.hbm2ddl.auto">create</property> <!-- <property name="hibernate_current_session_context_class">thread</property> --> <property name="current_session_context_class">thread</property> <mapping class="com.entity.Students"/> </session-factory> </hibernate-configuration> |
實體類Student：
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package com.entity; import java.io.Serializable; import java.util.Date; import javax.persistence.Column; import javax.persistence.Embedded; import javax.persistence.EmbeddedId; import javax.persistence.Entity;//JPA注解 import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.Table; import javax.persistence.Transient; import org.hibernate.annotations.GenericGenerator; /* * 學(xué)生實體類 *///@Entity// //@Entity(name="t_students")//如果不添加名字，則默認(rèn)與實體類名字相同，如果想要自行設(shè)置表明，就需要自己進(jìn)行添加 @Entity@Table(name="t_students1",schema="mypage") public class Students implements Serializable{ @Id// @GeneratedValue // @GeneratedValue(strategy=GenerationType.AUTO)//與@GeneratedValue結(jié)果相同，字符串類型不能指定為AUTO類型 // private int sid; //學(xué)號 // @GeneratedValue(generator="sid") // @GenericGenerator(name="sid",strategy="assigned") // @Column(length=11) // private String sid; @EmbeddedId private StudentPK pk; // @Id // // @Column(length=11) private String sname;//姓名 private String gender;//性別 private Date birthday;//出生日期 private String major;//專業(yè) private Address add; @Transient //表示該字段不會被ORM映射到表里的字段 private double salary;//薪水 public Students(){ } public Students(StudentPK pk, String sname, String gender, Date date, String major,Address add,double salary) { // super(); this.pk = pk; this.sname = sname; this.gender = gender; this.birthday = date; this.major = major; this.add = add; this.salary = salary; } public StudentPK getPk() { return pk; } public void setPk(StudentPK pk) { this.pk = pk; } public String getSname() { return sname; } public void setSname(String sname) { this.sname = sname; } public String getGender() { return gender; } public void setGender(String gender) { this.gender = gender; } public Date getBirthday() { return birthday; } public void setBirthday(Date birthday) { this.birthday = birthday; } public String getMajor() { return major; } public void setMajor(String major) { this.major = major; } public Address getAdd() { return add; } public void setAdd(Address add) { this.add = add; } public double getSalary() { return salary; } public void setSalary(double salary) { this.salary = salary; } } |
StudentPK實體類：
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package com.entity; import java.io.Serializable; import javax.persistence.Column; import javax.persistence.Embeddable; @Embeddablepublic class StudentPK implements Serializable{ /** * */ private static final long serialVersionUID = 1L; @Column(length=18) private String id;//身份證號 @Column(length=8) private String sid;//學(xué)號 public StudentPK(){ } public StudentPK(String id, String sid) { this.id = id; this.sid = sid; } public String getId() { return id; } public void setId(String id) { this.id = id; } public String getSid() { return sid; } public void setSid(String sid) { this.sid = sid; } @Override public boolean equals(Object obj) { // TODO Auto-generated method stub return super.equals(obj); } @Override public int hashCode() { // TODO Auto-generated method stub return super.hashCode(); } } |
地址類：
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package com.entity; import javax.persistence.Embeddable; import javax.persistence.Embedded; // 地址類 @Embeddable //表示是一個嵌入類，這個類的對象在另一個實體類中充當(dāng)屬性 public class Address { private String postCode;//郵編 private String address;//地址 private String phone;//聯(lián)系電話 public Address(){ } public Address(String postCode, String address, String phone) { this.postCode = postCode; this.address = address; this.phone = phone; } public String getPostCode() { return postCode; } public void setPostCode(String postCode) { this.postCode = postCode; } @Embedded public String getAddress() { return address; } public void setAddress(String address) { this.address = address; } public String getPhone() { return phone; } public void setPhone(String phone) { this.phone = phone; } } |
測試類：
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package com.entity; import java.util.Date; import java.util.EnumSet; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.Transaction; import org.hibernate.cfg.Configuration; import org.hibernate.service.ServiceRegistry; import org.hibernate.service.ServiceRegistryBuilder; import org.hibernate.tool.hbm2ddl.SchemaExport; import org.junit.Test; public class TestStudents { @Test public void testShemaExport(){ //創(chuàng)建hibernate配置對象 Configuration config = new Configuration().configure(); //創(chuàng)建服務(wù)注冊對象 ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().applySettings(config.getProperties()).buildServiceRegistry(); //生成SessionFactory SessionFactory sessionFactory = config.buildSessionFactory(serviceRegistry); SchemaExport export = new SchemaExport(config); export.create(true,true); } @Test public void addStudents(){ //創(chuàng)建hibernate配置對象 Configuration config = new Configuration().configure(); //創(chuàng)建服務(wù)注冊對象 ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().applySettings(config.getProperties()).buildServiceRegistry(); //生成SessionFactory SessionFactory sessionFactory = config.buildSessionFactory(serviceRegistry); //創(chuàng)建會話 Session session = sessionFactory.getCurrentSession(); //創(chuàng)建事務(wù) Transaction tx = session.beginTransaction(); Address add = new Address("700005","河南理工大學(xué)","15039117115"); StudentPK pk = new StudentPK("012345678912345678","55555555"); Students s = new Students(pk,"張三豐","男",new Date(),"太極拳",add,7899); session.save(s); tx.commit(); // SchemaExport export = new SchemaExport(config); // export.create(true,true); } } |
總結(jié)
以上就是本文關(guān)于hibernate屬性級別注解實例代碼的全部內(nèi)容，希望對大家有所幫助。在此也非常希望大家對本站多多支持。
原文鏈接：http://blog.csdn.net/wojiaohuangyu/article/details/51768672
